DABCO catalyzed pseudo multi-component synthesis of functionalized spirooxindoles

Green Synthesis of Spirooxindoles via Lipase-Catalyzed One-Pot Tandem Reaction in Aqueous Media

The development of non-natural enzymatic catalysis is important for multicomponent tandem organic transformations. However, the delicate acting environments of biological enzymes still present some challenges in the synthesis of spirooxindole skeleton via enzymatic catalysis. To address these issues, a lipase-catalyzed method was developed for the synthesis of spirooxindole frameworks. Using easily available isatins, cycloketones, and malononitriles as substrates, mild reaction conditions, and a reasonable reaction time, moderate to good yields (67–92%) and excellent functional group tolerance were accomplished via this protocol. The related mechanism explanation is also speculated in this paper.

Engaging Isatins in Multicomponent Reactions (MCRs) - Easy Access to Structural Diversity

Multicomponent reactions (MCRs) are a valuable tool in diversity-oriented synthesis. Its application to privileged structures is gaining relevance in the fields of organic and medicinal chemistry. Isatin, due to its unique reactivity, can undergo different MCRs, affording multiple interesting scaffolds, namely oxindole-derivatives (including spirooxindoles, bis-oxindoles and 3,3-disubstituted oxindoles) and even, under certain conditions, ring-opening reactions occur that leads to other heterocyclic compounds. Over the past few years, new methodologies have been described for the application of this important and easily available starting material in MCRs. In this review, we explore these novelties, displaying them according to the structure of the final products obtained.

Synthesis of Novel bis-spirooxindoles Catalyzed by Magnetic Cobalt Ferrite Encapsulated MCM-41@MgO as a Solid Base

AIMS AND OBJECTIVE

Synthesis of novel bis-spirooxindoles was carried out from isatins, two equivalents of malononitrile, and various derivatives of cyclohexanones.

BACKGROUND

A facile one-pot and four-component reaction was investigated for the synthesis of novel bisspirooxindoles from different derivatives of isatins, two equivalents of malononitrile and various derivatives of cyclohexanone in the presence of magnetic CoFe2O4@MCM-41@MgO NPS catalyst under mild conditions.

MATERIALS AND METHODS

Firstly, the magnetic CoFe2O4@MCM-41@MgO was prepared in three steps. Afterwards, the CoFe2O4@MCM-41@MgO was used as a base catalyst for the one-pot synthesis of bisspirooxindoles.

RESULTS AND DISCUSSION

The procedure exhibited several benefits, an excellent yield of products, short reaction times, reusability, and recyclability of the nanocatalyst.

CONCLUSION

The structure of nanocatalyst was recognized by FT-IR, XRD, VSM, SEM, BET, and EDX techniques, and the structure of the organic products was determined by melting point, FT-IR, 1H NMR, 13C NMR, Mass spectra, and C.H.N analyses.